The present invention relates to a hand-propelled cart for carrying relatively large and heavy objects such as electric refrigerators, electric washing machines, pieces of furniture, and cabinets, and more particularly to a hand-propelled cart especially suitable for carrying such objects up and down stairs or loading and unloading objects on and from a truck.
FIGS. 31 through 34 of the accompanying drawings illustrate a conventional hand-propelled cart or trolley. The prior cart includes a body 1' having an L-shaped side elevational configuration, main wheels 2' rotatably mounted on a lower portion of the body 1', and auxiliary wheels 3' rotatably mounted on an upper portion of the body 1', the main and auxiliary wheels 2' and 3' being spaced from each other by an adjustable interaxial distance. The principle of leverage can be used to manipulate the cart to move up and down stairs. More specifically, when moving the cart up a stair, the interaxial distance between the main and auxiliary wheels 2', 3' is adjusted to meet the width and height of a stair step. A handle 4' is depressed to turn the body 1' about the auxiliary wheels 3' on a step and is simultaneously pulled to bring the main wheels 4' onto the same step, as shown in FIG. 32. Then, the handle 4' is raised to turn the body 1' about the main wheels 2' and is simultaneously pulled until the auxiliary wheels 3' are landed on a next upper step. The cart can therefore be moved up stair steps by turning the body 1' about the main and auxiliary wheels 3', 4' alternately and lifting the main and auxiliary wheels 3', 4' alternately up one step at a time. The cart can similarly be moved down a stair by turning the body 1' about the main and auxiliary wheels 3', 4' alternately and lowering the main and auxiliary wheels 3', 4' alternately down one step at a time.
Where a stair has an intermediate landing 5' as shown in FIGS. 33 and 34, it has been impossible to bring the cart from steps onto the landing 5' or from the landing 5' onto steps through the leverage for the reason that the handle 4' would interfere with a wall surface 6' and could not be pulled. It has therefore been customary practice to keep the body 1' erected and lift the same onto the landing 5' or lower the same from the landing 5'.
When a heavy object is carried by the cart, however, it is difficult for one worker to put the cart onto or from the landing 5' and hence a plurality of workers have been required to do the job. This problem manifests itself when a high object such as a refrigerator is carried on a large-size cart.